98 Chevy Malibu Random No Electric at Start

I just had my water pump replaced last week by a sleazy shop that knocked my rearview mirror off and claimed it was like that when I dropped it off, siphoned a half a tank of gas and now my car has twice been completely dead with NO electric at start. All is blank and dead. The first time it started after I turned the key a few times and the clock had reset, the second time that didn’t do anything so I popped the hood and just touched the battery cables?it’s a newer battery adn the connections to it seem very secure.

My first thought was they must not have reconnected the battery cable securely that they removed to replace the pump. I can’t go back to them to have them double-check it.

I called the Chevy dealer and they want $176 to run an electrical diagnostic.

I’m at a loss. I can’t reach down in there where I see the battery cable stuff go under the block to check the connections myself.

Does anyone have any “sounds like xxxx” ideas? I just think it has to be way too much of a coincidence that this is happening after it being serviced by those jokers so that’s why I don’t think it’s the starter or that sort of thing but then again I have no idea. Thanks

I suggest you remove the battery connections and clean the posts and connections using a battery post cleaning brush. If that doesn’t fix the trouble then look for a bad connection on the smaller wire from the battery to the fuse panel under the hood. The main grounding from the battery could also be the trouble so check it also if you don’t finad something wrong on the positive side of the battery connections.